RFR: 8295808: GrowableArray should support capacity management

[Serguei Spitsyn]

On Sat, 22 Oct 2022 01:38:44 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

> Please review this change to GrowableArray to support capacity management.
> Two functions are added to GrowableArray, reserve and shrink_to_fit.  Also
> renamed the max_length function to capacity.
> 
> Used these new functions in StringDedupTable.
> 
> Testing: mach5 tier1-3

src/hotspot/share/utilities/growableArray.hpp line 544:

> 542:   if (len > 0) {
> 543:     new_data = static_cast<Derived*>(this)->allocate();
> 544:     for (int i = 0; i < len; ++i) ::new (&new_data[i]) E(old_data[i]);

This can be a stupid question as I'm confused a little bit.
Why do we reallocate memory for data elements?
Could we just move the element pointers from the `old_data`?
Then, of course, there would be no need to deallocate the moved data elements.

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PR: https://git.openjdk.org/jdk/pull/10827